San Francisco could become one of the first cities to require an electronic voting company to disclose the details of its software in an effort to ensure all votes are counted.

Electronic voting machines have stirred controversy as voter-rights activists say the machines cannot be trusted, especially since the software used to tally votes is kept secret.

More than 20 voter-rights advocates turned out at a Board of Supervisors Budget and Finance Committee hearing Wednesday to oppose the proposed $12.6 million four-year contract with Sequoia Voting Systems Inc.

Under the contract, The City would receive 610 optical scan voting machines (machines that read a paper ballot) and 610 touch-screen voter machines, intended for use only by the disabled.

“This system is going to be a paper-based system. It’s not going to be an electronic-based system. The voters aren’t going to see any difference at all,” said John Arntz, the city’s elections director.

Supervisor Chris Daly, chairman of the committee, postponed the vote on the contract until next week, putting pressure on Sequoia to agree to an unprecedented commitment to disclose its software details.

“I’m not prepared to move forward with this contract language without some public disclosure of your technology within the contract,” Daly said. “We’re willing to discuss this,” said Steven Bennett, representing Sequoia. Voting machine companies have kept their software private citing proprietary reasons.

Voter-rights advocates say that without a disclosure of the technology the public cannot trust that the machines are correctly counting the votes.

Arntz hopes to have the contract finalized in short order to prepare for the upcoming November election.

The existing voting machines are old and have posed problems in previous elections. In the most recent election, 35 percent of voting precincts required technical assistance, Arntz said. Built into the contract with Sequoia are penalties if the machines fail. For example, if just 10 percent of the machines break down on Election Day, the company would have to pay The City $150,000. “They have the incentive to make sure things run right,” Arntz said.